Answer:
The correct answer is 3: "<em>High levels of Ca2+ are expected to be found </em><em>within the sarcoplasmic reticulum</em>".
Explanation:
Muscular contraction is a highly regulated process that depends on free calcium concentration in the cytoplasm. Amounts of cytoplasmic calcium are regulated by <u>sarcoplasmic reticulum</u> that functions as a storage of the ion.
When a nerve impulse reaches the membrane of a muscle fiber, through acetylcholine release, the membrane depolarizes producing the entrance of calcium from <u>extracellular space</u>. The impulse is transmitted along the membrane to the sarcoplasmic reticulum, from where calcium is released. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. The calcium channel in the sarcoplasmic reticulum controls the ion release, that activates and regulates muscle contraction, by increasing its cytoplasmic levels. When <em>calcium binds to the troponin C</em>, <em>the troponin T alters the tropomyosin by moving it and then unblocks the binding sites,</em> making possible the formation of <em>cross-bridges between actin and myosin filaments.</em> When myosin binds to the uncovered actin-binding sites, ATP is transformed into ADP and inorganic phosphate.
Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
Answer:
<h2>A</h2>
Explanation:
1. Nucleus is a ball like structure which is found in the center of the cell only in eukaryotic cell, true nucleus is absent in prokaryotes.
2. Nucleus contains nucleic acid and is have double membrane which contain pores though which transport of molecules occurs.
3. DNA replication , transcription and RNA splicing occur in the nucleus.
Answer:
You would multiply by two i believe
Explanation:
I used to have to do those and thats what i was taught. Have A Nice Day :)
The answer is; medulla oblongata and pons.
In this region of the brain, there are chemoreceptors that can detect changes in the pH of the blood. These are called central chemoreceptor. There are also chemoreceptors in the arteries called peripheral chemoreceptors. When these chemoreceptors detect a drop in the blood PH (due to increased dissolved carbon dioxide in the blood), the depth and rate of breathing is increased in the lungs.
Answer:
the skin cells prevent germs from coming in our bodies
Explanation:
